Expanding rotary underreamer



April 21, 1931.

l.. s. coPELlN 1,801,265

EXPANDING ROTARY UNDERREAMER Filed March 2l, 1928 2 Sheets-Sheet l` April 21, 1931. 1 s. coPELIN EXPANDING ROTARY UNDERREAMER 2 Sheets-Sheet 2 Filed March 2l, 1928 Patented Apr. 21, 1931 PATENT y OFFICE LEONARD'S. COPELIN, OF LOS ANGELES, CALIFORNIA EXPNDING ROTARY UNDERREAMER Application led March 21, 1928. Serial N'o. 263,331.

My invention relates to the art of drilling oilwells and the like, being more particularly an underreamer of the rotary type. In the drilling of oil wells, lit is customary. to

.clean tliesides of the hole after the drilling tool has advanced, so thatthe string of pipe to be set may be readily lowered into proper position without friction, and for this purpose, it is customary to use an underreamer lowhich cuts the holeto a suiliciently large di' ameter above the bit to permit the string of pipe to be set.

Underreamers, whether of the blade type, or the type in which rotary cutters are em- ,1W ployed, usually are provided with positive means for expanding theunderreaming elements, which positive means is operated by means of movable parts in the body of the underreamer, which, in turn, are operated to 2 movelongitudinally with respect to the'body of the underreamer. Y

It is the principal object of my invention to produceA an underreamerV of the rotary cutter type, of simple form' and construction, Tin which no sliding membersV are used for expanding the cutters and in which the action of the cutters is entirely automatic and operated by engagement with the sides of the hole. Y y

The object justreferred'to is accomplished byfinounting a plurality ofrotatable cutting,r

units in the body `of the underreamer, such roc tary cuttingV elements being slidabl'e longi- `tudinally within fixed limits, and so arranged that' engagement by the rotary cutting elements of the sides of the hole move such cutting elements upwardly `and out-V wardly into expanded position, so as toenlarge the hole to a suiiicient diameter to receive thecasing, the cutting units moving into Van inoperative position upon upward movement of the drilll string. y

Otherk objects and` advantages will appear hereinafter from the following specification and the accompanying drawings. l

lReferring to the drawings, which are for 50 a portion of an underreamer body,lshowing a form of my invention, the cutting units being shown in expanded position.

Fig. 2 is a. view similar to Fig. l, showing the cutting elements in retracted or inoperative position. ab

Fig. 3 is a sectional plan view on line 3-3 of Fig. l. i

Fig. 4 is a sectional plan view on line 4-4 of Fig. l. y Fig. 5 is a sectional plan view on line 60 5 5 of Fig. 2.

Fig. 6 is an inverted sectional plan view on line 6-6 of Fig. l.

Fig. 7 is a` perspective view of one of the rotary cutter units. .i Fig. 8 is a. perspective view of a bearing block of one of the cutter units.

Fig. 9 is a perspective view of a filler block. Fig. 10 is a perspective view of a retaining ring used for holding the bearing blocks in proper position, and

Fig. 11 is an assembled View von a smaller scale of the entire underreamer and connections, as the same appear passing through y the casing in the well.

More specifically describing the embodiment of my invention as shown in the accompanying drawings, 11 designates a reamer body, circular in cross section, being interiorly threaded at its upper end to receive s a sub 12 for attachment to drill collar l3,`the

lower end of the reamer body terminating in a reduced threaded portion lll, to which is attached a sub l5, for attachment of any suitable form of bit, the upper end of which is indicated at 16, as shown in Fig. Il.

A plurality of reamer units are employed, in the form shown there being three such units, generally indicated at 20, each being mounted in a. recess 2l, formed in the side of the reamer body. Each cuttingl or reaming unit 20 consists of a crank shaft 22, having offset ends 23 and 24, the end 23 being fixed to an extension 25 on the main portion of the shaft by means of a pin 26 which may be secured therein by wel-ding or other suitable manner. The upper end 23 of the crank shaft is rotatably received in a bore 27 in the upper face of the recess 2l, a thrust bearing 28 being provided in the form of a ball bearing, as clearly shown in Figs. 1 and 2.

The lower end 24 of the crank shaft is ro-y tatably received in a bore 30, extending into the upper end of a bearing block 31, mounted in a guide way or slot 32, extending downwardly from the recess 21.

This block 31 is shouldered, asl indicated I at 33, toform a seat for offset lower end of 'v the crank portion of the crank shaft 22, bevel facesr'34 and 35 being formed at the rear of said shoulder 33 to facilitate the expulsion of cuttings from the shoulder and behind the crank when the cutting or reaming eleof the recess 21.

Each cutter unit 20 is assembled in the followingmanner: The reamer 36 is placed on the crank portion of the recess and a "washer 41 placed thereon, after which the end 23 is secured to the crank portion of the shaft, as

above described. The upper end 23 is then inserted in the bore 27, the lower end 24 being placedin the bearing block and such block laced in the slot 32, being retained in place y means ofa ring 43 on a reduced portion 44 ofthe reamer body, such ring being held in place by means of the sub 15. YThe slot 32 extends below the lower endiof the block 31 to afford sufficient movement of the block to permit the end 23 of the crank shaft to be inserted as above described, a filler block 43 being placed in the slot below the bearing block 31.V Means are provided for discharging circulating fluid intothe'recesses 21, which consist of al series of ducts or passages 45, shown in Fig. 6, and such ducts connect with a l chamber 46 as indicated in Fig. 11. A central Viuid passage 47 extends longitudinally throughout the underreamer to supplyuid to the bit. V f f rlhe operation of the underreamer is as follows: In the position shown in Fig. 11, the

underreamer may be considered as passing downwardly through the casing 50, in which lposition it will be noted that the cutters or reamers 36 extend laterally slightly beyond the walls of the underreamerbody. While in this position, the reamers are retracted and the crank portion of the crank shaft rests upon the shoulder 33 on the bearing block,

this retracted position of the reamers being alsov illustrated in Figs. 2 and 5.

As .the tool in itsV downward movement reaches apoint where theV reamers36 engage' the lsides of the hole, indicated at'51, the

tion of the crank shaft 22, slide upwardly thereon, the beveled end 39 of the reamers engaging their respective guides 40 and moving the reamers outwardly. f

This action ofthe guides is to assist the reamers into moving into expanded position, but the outward movementof the reamers is primarily caused bythe engagement of the reamers with the walls of theV hole and the rotary movement of the underreamer body, as indicated by the arrow -53 in Fig. 4. The downward movement of the kunderreamer and the rotative movement of the underreamer cause the crank shafts with the reamers thereon toswing outwardly in the direction of the arrow 54 in Fig."5,which outward movement is limited bythe engagement of thecrank portion of the crank shaft,lwithk an abutment 55 on the bearing block 3 1.

Y When the reamers are in the expanded. position shown in Figs. 1 and 4, the formation is cut away to a diameter permitting the lowering of the casing as maybe desired.

The reamers are retracted by an upward n movement and a reverse rotative movement yof the underreamer body from that just described, the crank shafts and reamers thereon being free to return' to their original position. i While lI have shown a preferred embodiment of my invention, it is to be understood that modifications of the construction shown may be made by those skilled inthe art without vdeparting from the spirit of my in-,` vention. l claim as my invention:

1. An underreamer comprising abody, Va plurality of crank shafts having offset ends mounted on said body, a rotatable reamer on each crankshaft, and means for limiting V the rotative movement of said crank shafts. 2. An underreamer comprising a body, a plurality ,of reamer units mounted in said body, each reamer unit consisting of a crank on said block for limiting the rotative movement of said crank shaft, and means for re-' taining said block on the reamer body.

k4. An underreamer comprising a body Yhaving a plurality of reamer recessesv therein, a rotatable reamerswingably mounted in each recess, and stationary guide means en- K gageable with the upper end of each rotatable reamer 'toswing said reamer into operative position. Y' f" 5. An underreamer comprising a body, a plurality of crank members mounted in said body, and a reamer on each crank member slidably and rotatably mounted thereon.

6. An underreamer comprising a body, a

plurality of crank members mounted in said body, a reamer on each crank member slidably and rotatably mounted thereon, and means for limiting the rotative movement of said crank members.

7. An underreamer comprising a body, a plurality of rotatable reamers swingably mounted thereon, and means operable by engagement of the reamers with the formation followed by a downward movement of said body relative to said formation to swing'said reamers outwardly with respect to the longitudinal axis of said body.

8. An underreamer comprising a body, a plurality of rotatable reamers swingably and slidably mounted thereon, means operable by engagement of the reamers with the formation to swing said reamers outwardly with respect to the longitudinal axis of said body, and means engageable by said reamers during theirl sliding movement to direct the reamers in their outward movement.

9. An underreamer comprising: a body; a plurality of crank members rotatably mounted in said body; a reamer slidably and rotatably mounted on each crank member; and means operable upon sliding of said reamers to rotate said crank members.

10. An underreamer comprising: a body; a plurality of crank members rotatably mounted in said body; a reamer slidably and rotatably mounted on each crank member; means operable upon sliding of said reamers to rotate said crank members; and means for limiting the rotative movement of said crank members.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this V12 day of March, 1928.

LEONARD S. COPELIN. 

